Why We Lie: The Source of our Disasters. Dorothy Rowe

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      The last twenty years has seen some huge advances in science. Scientists have not kept this knowledge to themselves. Many of them have written excellent books in which they not only explain their science to non-scientists but they do so in a way which excites their readers’ continuing curiosity. When the science can be combined with wonderful pictures, a good script and an interesting presenter, we watch in our millions. However, when the science concerns the natural world, or geology, or geography, or astronomy what we are being told is out there, separate from us. Being told about climate change is somewhat worrying, but then we can delude ourselves it won’t happen in our lifetime. But, when it comes to how our brains function or how we perceive, we cannot separate ourselves from the science. This is difficult enough when we are watching a television programme about cancer or about a nasty operation being performed, but how do we deal with what Chris Frith, Emeritus Professor of Neuropsychology at University College London, is telling us when he writes, ‘Even if all our senses are intact and our brain is functioning normally, we do not have direct access to the physical world. It may feel as if we have direct access, but this is an illusion created by our brain’?²

      Computers have been around long enough for us not to be disturbed by the idea that the brain is a kind of computer. Twenty-odd years ago neuroscientists took this metaphor seriously. Now they know that the brain is not like a computer. Unfortunately, some aspects of the brain as a computer metaphor have proved to be very popular. If you have a bad temper, it is not your fault because you were programmed early in life to be bad tempered. Those of us who have no religious beliefs are likely to be told by godly people that religious belief is ‘hard-wired’ into every brain, including ours. It is difficult to give up a self-serving metaphor, especially when the new metaphor, which is closer to the truth, is difficult to comprehend.

      The neuroscientist Marco Iacoboni pointed out that, just as the casing of a computer is simply a container for the memory and the software of the computer, so, in the computer metaphor, ‘mental operations are largely detached from the workings of the body, with the body a mere output device for commands generated by the manipulation of abstract symbols in the mind’. However, it is now clear that ‘our mental processes are shaped by our bodies and by the types of perceptual and motor experiences that are the product of their movement through and interacting with the surrounding world’.³ Our mind is shaped by the way our body interacts with the world around us. Thus our brain contains maps of, say, our hand curving around a cup and of our body balancing itself as we walk over rough ground.

      When I was a psychology undergraduate in 1948, we were taught that, in our interactions with the world, first we had a sensation, then a perception, and then a response which was some kind of action. Over the following years, neuropsychologists accepted what researchers were telling them, namely that sensation and perception were one process. It was still assumed that perception and action were completely independent processes. Iacoboni is one of the neuroscientists researching the functions of what have been called mirror neurones that are located in the premotor cortex. These neurones seem to be an essential part of our ability to imitate others. What this research has shown is that perception and action are not separate functions in our brain but are ‘simply two sides of the same coin, inextricably linked to each other’. Iacoboni explained, ‘In the real world, neither the monkey nor the human can observe someone else picking up an apple without also invoking in the brain motor neurone plans necessary to snatch that apple themselves… In short, the grasping actions and the motor plans necessary to obtain and eat a piece of fruit are inherently linked to our very understanding of the fruit.’⁴ That is, if your brain did not already contain a picture of what an apple was and how it could be eaten, you would not create motor plans to snatch the fruit, unless, perhaps, you had no knowledge of good manners and were so overcome with curiosity that you planned to seize and examine this strange thing.

      What I had been taught all those years ago is now called the sensory-motor model of human action, whereas now we have the ideomotor model which ‘assumes that the starting point of actions are the intentions associated with them, and that actions should be mostly considered as means to achieve those intentions’.⁵ If you want to understand another person (or yourself) you need to know not just what that person does but why he does it.

      In short, our brain interprets the world, and our interpretations become our intentions in acting on the world. But, if our interpretations are only guesses about our world, how can we assess whether our actions are likely to be successful? Answer: with our Bayesian brains.

      Thomas Bayes was an eighteenth-century Presbyterian minister and mathematician. He created a mathematical theorem concerning the probability of an event occurring changing as more information is accumulated. A famous example of Bayesian brains at work is that scene where people are looking up into the sky and asking, ‘Is it a bird? A plane? No, it’s Superman.’ In this case, the Bayesian brain is working out the probability of the hypotheses of, first, a bird, then, a plane, and, with the best evidence, Superman himself, a conclusion, all without conscious effort on the part of the observers. Computers can use Bayesian methods of calculating the probabilities that arise in very complex data. As a Presbyterian, Bayes would have been pleased that his statistical method is used in computers to filter out immoral spam. My computer manages to identify all those email offers of Viagra and penis extension, but, unfortunately, it cannot distinguish these from the emails from that very august establishment The Sydney Institute in the city of that name. My Bayesian brain knows the difference, but my Bayesian computer does not.

      We can make grave errors in deciding the probability of a particular event, but, according to Chris Frith,

      Our brains are ideal observers when it comes to making use of the evidence from our senses. For example, one problem our brain has to solve is how to combine evidence from our different senses. When we are listening to someone, our brain combines the evidence from our eyes – the sight of their lips moving – and from our ears – the sound of their voice. When we pick something up, our brain combines the evidence from our eyes – what the object looks like – and from our sense of touch – what the object feels like. When combining this evidence, our brain behaves just like the ideal Bayesian observer. Weak evidence is ignored; strong evidence is emphasized. When I am speaking to the Professor of English at a very noisy party, I will find myself staring intently at her lips, because in this situation the evidence coming through my eyes is better than the evidence coming through my ears.⁶

      When I am lecturing, I make constant assessments of the probability that my audience is interested in what I am saying. When I am talking about how we operate in the world, the response from most people suggests that they have not encountered the idea that they cannot see reality directly, or that the brain calculates probabilities in making a guess about what might be going on. I find that my audiences listen with a degree of attentiveness that they do not show when I am talking about matters with which they are familiar. I found this even in an audience comprised of highly educated people who placed great value on education. These were the parents of students at a famous public school. I had been asked to talk about communication between parents and their children. To explain why communication so often failed I needed to begin by explaining how we operate as human beings.

      I have given this part of my lecture many times. I usually begin with something which I acquired from Ian Stewart, the Professor of Mathematics at Warwick University, but which I now pass off as my own.

      Standing in front of my audience and with appropriate gestures, I say, ‘As I stand here everything seems totally real. I’m here, you’re over there, and beyond you are the walls, and beyond that what I can see through the windows. But actually, that isn’t what is happening. I have no idea what is actually here. What is happening СКАЧАТЬ